The extraordinary commotion on July 20, the penultimate night of the four-day convention, reflected the difficulty Republicans have had in rallying party members behind the bombastic and raucous campaign that Trump has waged.

The billionaire real-estate tycoon defeated 16 other candidates during the primary season despite never holding elected office and despite espousing policy positions that many, including senior Republican leaders, have called divisive, alienating, and xenophobic.

Cruz, an evangelical Christian lawyer, came in second behind Trump, and Trump had routinely insulted Cruz as “Lyin’ Ted.” Cruz labeled Trump a “serial philanderer.”

Republicans leaders had hoped the convention being held in Cleveland, Ohio, would help unite the party behind Trump and give him momentum going into the November 8 election against the likely Democratic nominee, Hillary Clinton.

In his speech, Cruz echoed some of Trump’s policy proposals, including endorsing Trump’s plan to build a wall that he said would stop immigrants from Mexico from entering the United States.

And he congratulated Trump on winning the nomination, but he ended his speech without endorsing Trump. That prompted the extraordinary scene of delegates booing him on live national television and chanting “Keep Your Pledge” -- a reference to the pledge all Republican candidates made to endorse the winner of the primary campaign.

"And to those listening, please, don't stay home in November," he said. "If you love your country, and love your children as much as I know that you do, stand, and speak, and vote your conscience, vote for candidates up and down the ticket who you trust to defend our freedom and to be faithful to the constitution.”

As Cruz closed out his speech, TV cameras showed Trump on one part of the arena floor, shaking hands and waving, a move many observers interpreted as undermining Cruz.

CNN, meanwhile, reported that security officials had to escort Cruz’s wife out of the arena as some delegates yelled at her.

The first two nights of the convention have been widely seen as uneven and at times lackluster, with a roster of unusual speakers and litany of accusations against the presumptive Democratic nominee, former Secretary of State Hillary Clinton.

Clinton, who is due to gain the Democratic Party's formal nomination next week, was the repeated target of vitriol on July 20. As they did during previous sessions, many of the nearly 2,000 delegates in attendance repeatedly chanted “Lock Her Up! Lock Her Up!” during the speeches.

“At the very moment, when America is crying out for something new and different, the other party has answered with a stale agenda, and the most predictable of names,” Pence said.

“People in both parties are restless for change, ready to break free of old patterns in Washington and Democrats are about to anoint someone who represents everything the country is tired of. Hillary Clinton wants a better title, and I would, too, if I was already secretary of the status quo,” he said.

Earlier, Newt Gingrich, a former speaker of the House of Representatives who was passed over by Trump to be his running mate, insisted that Islamic terrorists were “winning the war” against the West, citing recent terror attacks in Nice, Paris, and Brussels.

“We cannot let ourselves grow numb to these accumulating atrocities,” Gingrich said. “Let’s be clear: Donald Trump is right. We are at war with radical Islamists. We are losing the war. And we must change course to win the war.”

The convention was earlier overshadowed by accusations that Trump's wife, Melania, plagiarized parts of a speech made by Barack Obama’s wife, Michelle, in 2008. On July 20, an employee for Trump’s business issued a statement admitting she was responsible for lifting the passages unattributed, and apologizing.

Outside the convention hall, protests heated up on July 20. While police reported only five people detained in the previous two days, at least 17 people were arrested when a demonstration to burn an American flag turned rowdy.

One group that identified itself as communist tried to burn a flag, but officers swarmed the group just seconds after it was set alight, sparking scuffles and pushing. Cleveland police later said in a message posted on Twitter that officers and firefighters moved in because the flames had set a man's pants on fire.

The protest was the most chaotic since the convention began July 18, and briefly prevented delegates and members of the media from getting into the arena for the evening events.

Law-enforcement officials had feared worse, however, In the wake of terrorist attacks in Florida and California, the police shootings in Dallas, and the protests over the police killing of two black men.